Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar position alignment using 3-dimensional semi-automated measurements on WBCT. Fourteen patients (15 ankles, mean age 61) who underwent TAR for varus ankle OA were retrospectively analyzed using semi- automated measurements of the hindfoot based on pre-and postoperative weightbearing WBCT (WBCT) imaging. Eight 3-dimensional angular measurements were obtained to quantify the ankle and subtalar joint alignment. Twenty healthy individuals were served as a control groups and were used for reliability assessments. All ankle and hindfoot angles improved between preoperative and a minimum of 1 year (mean 2.1 years) postoperative and were statistically significant in 6 out of 8 angles (P<0.05). Values The post-op angles were in a similar range to as those of healthy controls were achieved in all measurements and did not demonstrated statistical difference (P>0.05). Our findings indicate that talus repositioning after TAR within the ankle mortise improves restores the subtalar position joint alignment within normal values. These data inform foot and ankle surgeons on the amount of correction at the level of the subtalar joint that can be expected after TAR. This may contribute to improved biomechanics of the hindfoot complex. However, future studies are required to implement these findings in surgical algorithms for TAR in prescence of hindfoot deformity

Introduction. Among patients with ankle osteoarthritis (OA) a post-traumatic origin is much more frequent than among those with knee or hip OA. However, long-term studies evaluating risk factors for the development of OA after ankle fractures are lacking. Methods. Retrospective cohort study including consecutive patients operated at our institution between 1/1988 and 12/1997 for malleolar fractures treated with open-reduction and internal fixation (ORIF). Ankle OA was independently assessed by two reviewers on standardized radiographs using the Kellgren and Lawrence (K&L) scale. Multivariate logistic regression analysis was performed to determine predictors for OA. Results. 374 patients (56% men) underwent ankle surgery during the study period. 9% had a Weber A, 58% a Weber B and 33% a Weber C fracture. Mean age at operation was 42.9 years. 12–22 years after surgery, 47 patients had died, 126 were lost to follow-up, and 99 did not respond or refused to participate. 102 patients were available at follow-up (similar age, gender, BMI and type of fracture than those not seen). Mean follow up was 17.3 years. Advanced OA (K&L 3–4) was present in 37 patients (36.3%). Significant risk factors for advanced OA were: fracture type (Weber C 53% vs. Weber B 31% vs. Weber A 0%, p = 0.006), presence of medial malleolus fracture, fracture-dislocation, increasing BMI, older age, and longer follow-up time. Conclusion. Advanced ankle osteoarthritis is frequent (36%) 12–22 years after a malleolar fracture, especially after Weber C fractures, medial malleolus fractures or fracture-dislocation. Obese and older patients are at increased risk

Introduction:. Symptomatic treatment of ankle osteoarthritis (OA) with corticosteroid injections is well established. Hyaluronic acid is also reported as an effective symptomatic treatment for ankle OA but these two treatments have not been compared directly. Methods:. A prospective randomised controlled trial in patients with symptomatic ankle osteoarthritis. Twenty patients per group were required based on a significance level of 0.05, and a drop out rate of 5%. Patients were blindly allocated to the treatment or control group. Injections were carried out by the clinician in the outpatient department. Treatment group received Ostenil 20 mg and control group received Depomedrone 40 mg (both as single injections). The treatment arm was allocated by computer generated block randomization to match treatment allocation with grade of arthritis. The primary outcome measure was the change in Visual Analogue Scale (VAS) pain score at 6 months. Secondary outcome was the change in AOFAS score at 6 months. Research ethics committee approval was obtained. Results:. A total of 42 patients were recruited of which 38 completed the study. Male recruits predominated (79%; 33 recruits). More than 70% had radiographic OA of grade 3 or more. Both groups demonstrated statistically significant improvements in VAS at weeks 3, 6, and 3 months over baseline, but the Ostenil group faired better at 6 months follow-up. (difference in VAS scores of 3.5 Ostenil VAS − 4; Steroid VAS − 7.5; Mann Whitney test (p<=0.05). There was no statistical difference in AOFAS scores between both groups at baseline and follow-up (p=0.48, Mann Whitney test). No complications noted. 30% of patients have had their surgical procedures delayed for 6 month post injection. Conclusion:. The Ostenil group revealed similar clinical efficacy to steroid group, however the benefits provided by Ostenil lasted longer. Ostenil provided sufficient mid-term pain-relief whilst patient awaits further definitive intervention

Background. Until recently, surgical treatments for advanced ankle osteoarthritis have been limited to arthrodesis or ankle replacement. Supramalleolar osteotomy provides a joint-preserving option for patients with eccentric osteoarthritis of the ankle, particularly those with varus or valgus malalignment. Aim. To evaluate radiological and functional outcomes of patients undergoing shortening supramalleolar osteotomy for eccentric (varus or valgus) osteoarthritis of the ankle. Method. Prospective review of patients from 2008 onwards. Osteotomy was the primary surgical procedure in all patients after failure of non-operative measures. Pre-operative standing antero-posterior and Saltzman view radiographs were taken to evaluate degree of malalignment requiring correction. Radiological and clinical outcomes were assessed at 3, 6 and 12 months post-operatively. Radiographs were reviewed for time to union. Patients were assessed on an outpatient basis for ankle range of motion as well as outcomes using AOFAS scores. Results. 33 patients over a 7 year period. Mean follow-up was 25 months (range 22–30). Mean time to radiological union was 8.6 weeks (range 8–10); there were no cases of non-union. There was a statistically significant improvement in functional scoring (P< 0.001); mean AOFAS score improved from 34.8 (range 15–40) pre-operatively to 79.9 (range 74–90) at 12 months post-operatively. There was no significant change in pre- and post-operative range of motion. 2 patients required revision surgery at 12 months; one to arthrodesis and one to ankle replacement. Conclusion. Supramalleolar osteotomy is a viable joint preserving option for patients with eccentric osteoarthritis of the ankle. It preserves motion, redistributes forces away from the affected compartment and corrects malalignment, providing significant symptomatic and functional improvement

Until recently, surgical treatments for advanced ankle osteoarthritis have been limited to arthrodesis or ankle replacement. Supramalleolar osteotomy provides a joint-preserving option for patients with eccentric osteoarthritis of the ankle, particularly those with varus or valgus malalignment. The aim of the study was to evaluate radiological and functional outcomes of patients undergoing shortening supramalleolar osteotomy for eccentric (varus or valgus) osteoarthritis of the ankle. We performed a prospective review of patients from 2008 onwards. Osteotomy was the primary surgical procedure in all patients after failure of non-operative measures. Pre-operative standing antero-posterior and Saltzman view radiographs were taken to evaluate degree of malalignment requiring correction. Radiological and clinical outcomes were assessed at 3, 6 and 12 months post-operatively. Radiographs were reviewed for time to union. Patients were assessed on an outpatient basis for ankle range of motion as well as outcomes using AOFAS scores. 33 patients were reviewed over a 7 year period. Mean follow-up was 25 months (range 22–30). Mean time to radiological union was 8.6 weeks (range 8–10); there were no cases of non-union. There was a statistically significant improvement in functional scoring (P<0.001); mean AOFAS score improved from 34.8 (range 15–40) pre-operatively to 79.9 (range 74–90) at 12 months post-operatively. There was no significant change in pre- and post-operative range of motion. 2 patients required revision surgery at 12 months; one to arthrodesis and one to ankle replacement. Supramalleolar osteotomy is a viable joint preserving option for patients with eccentric osteoarthritis of the ankle. It preserves motion, redistributes forces away from the affected compartment and corrects malalignment, providing significant symptomatic and functional improvement

Purpose: To determine, the foot pressure pattern in ankle osteoarthritis before and after ankle fusion. To compare the results with those of normal individuals. Method: The distribution of plantar pressures of the foot has been measured by different means ranging from crude methods to modern techniques using transducers in the form of mats and insole devices. A less cumbersome in-sole transducer called FSCAN sensor has become commercially available. This device has been used to measure dynamic pressures at the Shoe-Foot interface in normal people and in pathological conditions in the foot. However the pressure distribution in the soles of patients with ankle osteoarthritis has not been studied. We present a prospective case control study of 18 participants (9 with ankle osteoarthritis and 9 controls). Ethical approval was obtained for this study. The controls were matched to cases by foot shape, gender and weight. The pressure measurement device, technique of ankle fusion and post operative protocol (for the arthritis patients) were standardised for all the participants. The Ankle-Hindfoot Scale and SF-36 Health Survey scores were obtained pre-operatively and at six months post-operatively and compared. Results: There were four females and 14 males. The average age was 67 years. The forefoot in patients with arthritis bore more weight compared to controls and this was statistically significant (P< 0.05). The forefoot pressure was also higher than the hind foot pressure in the patients, both preoperatively and post operatively. This was also statistically significant, (P< 0.05). The Ankle-Hindfoot Scale improved significantly postoperative, (P< 0.05). There was no statistically significant difference in the SF-36 Health Survey scores. Conclusion: The study shows that ankle osteoarthritis changes the pressure distribution in the foot, with preponderance in the forefoot. It also shows that after ankle fusion there is a change in the pressure. However, the forefoot still bears more pressure compared to the hind foot. The result may help in predicting areas of the foot at risk in developing problems due to high pressure load post ankle fusion. It may also help in designing foot orthosis in the peri-operative management of the foot in ankle osteoarthritis

Background. Occasionally, patients experience new or increased ankle pain following total knee arthroplasty (TKA). The aims of this study were to determine (1) how the correction of varus malalignment of the lower limb following TKA affected changes in alignment of the ankle and hindfoot, (2) the difference in changes in alignment of the ankle and hindfoot between patients with and without ankle osteoarthritis (OA), and (3) whether the rate of ankle pain and the clinical outcome following TKA differed between the 2 groups. Methods. We retrospectively reviewed prospectively collected data of 56 patients (99 knees) treated with TKA. Among these cases, concomitant ankle OA was found in 24 ankles. Radiographic parameters of lower-limb, ankle, and hindfoot alignment were measured preoperatively and 2 years postoperatively. In addition, ankle pain and clinical outcome 2 years after TKA were compared between patients with and without ankle OA. Results. The orientation of the ankle joint line relative to the ground improved from varus 9.4° to varus 3.4°, and the valgus compensation of the hindfoot for the varus tilt of the ankle joint showed a 2.2° decrease following TKA. Patients in the group with ankle OA showed decreased flexibility of the hindfoot resulting in less preoperative valgus compensation (p = 0.022) compared with the group without ankle OA. The postoperative hindfoot alignment was similar between the 2 groups because of the smaller amount of change in patients with ankle OA. The group with ankle OA had a higher rate of increased ankle pain (38% compared with 16%) as well as a worse Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score (mean of 22.2 compared with 14.2) following TKA. Conclusions. A considerable proportion of patients who underwent TKA had concomitant ankle OA with reduced flexibility of the hindfoot. These patients experienced increased ankle pain following TKA and a worse clinical outcome

Background: While several studies in the last years tried to identify clinical limitations of patients suffering from end-stage ankle osteoarthritis (OA), very few attempted to assess foot and ankle function in a more objective biomechanical way, especially using dynamic pedobarography. The aim of the study was therefore to explore plantar pressure distribution characteristics in a large cohort of posttraumatic end-stage ankle OA. Method: 120 patients (female, 54; male, 66; 120 cases) suffering from posttraumatic end-stage ankle OA were included. The clinical examination consisted of assessment of the AOFAS hindfoot score, a pain score, the range of motion (ROM) for ankle dorsiflexion and plantar flexion, and the body mass index (BMI, kg/m2). Radiological parameters included the radiological tibiotalar alignment and the radiological ankle OA grading. Plantar pressure distribution parameters were assessed using dynamic pedobarography. Results: Intra-individual comparison between the affected and the opposite, asymptomatic ankle revealed significant differences for several parameters: maximum pressure force and contact area were decreased in the whole OA foot, such was maximum peak pressure in the hindfoot and toes area. No correlations could be found between clinical parameters, such as AOFAS hindfoot score, VAS for pain, and ROM, and the pedobarographic data. However, there was a positive correlation between dorsiflexion and the pedobarographic parameters for the hindfoot area. Conclusion: In conclusion, posttraumatic end-stage ankle OA leads to significant alterations in plantar pressure distribution. These might be interpreted as an attempt of the patient to reduce the load on the painful ankle. Other explanations might be bony deformity and ankle malalignment as a consequence of either the initial trauma or of the degenerative process itself, pain related disuse atrophy of surrounding muscles, and scarred soft tissue

Introduction. Deformity of knee joint causes deviation of mechanical axis in the coronal plane, and the mechanical axis deviation also could adversely affect biomechanics of the ankle joint as well as the knee joint. Particularly, most of the patients undergoing total knee arthroplasty (TKA) have significant preoperative varus malalignment which would be corrected after TKA, the patients also may have significant changes of ankle joint characteristics after the surgery. This study aimed 1) to examine the prevalence of coexisting ankle osteoarthritis (OA) in the patients undergoing TKA due to varus knee OA and to determine whether the patients with coexisting ankle OA have more varus malalignment, and 2) to evaluate the changes of radiographic parameters for ankle joint before and 4 years after TKA. Methods. We evaluated 153 knees in 86 patients with varus knee OA who underwent primary TKA. With use of standing whole-limb anteroposterior radiographs and ankle radiographs before and 4 years after TKRA, we assessed prevalence of coexisting ankle OA in the patients before TKA and analyzed the changes of four radiographic parameters before and after TKA including 1) the mechanical tibiofemoral angle (negative value = varus), 2) the ankle joint orientation relative to the ground (positive value = sloping down laterally), 3) ankle joint space, and 4) medial clear space. Results. Of the 153 knees, 59 (39%) had radiographic ankle OA. The knees with ankle OA had significantly more varus mechanical tibiofemoral angle preoperatively than those without ankle OA (− 11.9° vs. − 9.3° on average, respectively; P = 0.003). Compared to the preoperative condition, the ankle joint orientation relative to the ground significantly changed after TKA (from 9.0° to 4.8° on average, P<0.001) while ankle joint space and medial clear space did not. Conclusions. Our study revealed that coexisting ankle OA would be common in patients with varus knee OA, particularly in patients with more varus malalignment. TKA also significantly changes the ankle joint orientation relative to the ground which shows more parallel to the ground. However, its effect on ankle joint space and medial clear space seems to be minimal upto 4 years after TKA. Our findings warrant consideration in preoperative evaluations of ankle OA in varus knee OA patients undergoing TKA, and further studies should evaluate prospectively the clinical implications of radiographic change of the ankle joint after TKA

Introduction. Currently, a validate scale of ankle osteoarthritis (OA) is not available and different classifications have been used, making comparisons between studies difficult. In other joints as the hip and knee, the Kellgren-Lawrence (K&L) scale, chosen as reference by the World Health Organizations is widely used to characterize OA. It consists of a physician based assessment of 3 radiological features: osteophyte formation, joint space narrowing and bone end sclerosis described as follows: grade 0: normal joint; grade 1: minute osteophytes of doubtfull significance; grade 2: definite osteophytes; grade 3: moderate diminution of joint space; grade 4: joint space greatly impaired, subchondral sclerosis. Until now, the K&L scale has never been validated in the ankle. Our objective was to assess the usefulness of the K&L scale for the ankle joint, by determining its reliability and by comparing it to functional scores and to computerized minimal joint space width (minJSW) and sclerosis measurements. Additionally we propose an atlas of standardized radiographs for each of the K&L grades in the ankle. Methods. 73 patients 10 to 20 years post ankle ORIF were examined. Bilateral ankle radiographs were taken. Four physicians independently assessed the K&L grades and evaluated tibial and talar sclerosis on anteroposterior radiographs. Functional outcome was assessed with the AOFAS Hindfoot score. Bone density and minJSW were measured using a previously validated Ankle Image Digital Analysis software (AIDA). Results. The interobserver reliability, for the K&L stages was 0.60 (intraclass correlation coefficient) indicating moderate to good agreement. The mean AOFAS hindfoot score decreased substantially (p = 009) and linearly from 99.3 in K&L grade 0 to 79.5 points in K&L grade 4. The minJSW assessed by AIDA was similar among grades 0 to 2 (between 2 and 2.5mm), but significantly lower in grade 3 (1.8mm) and in grade 4 (1.1mm). A decreased minJSW less than 2mm, commonly used as a threshold for the assessment of hip and knee OA, was found in 77% of K&L grades 3–4 compared to 33% of grades 0–2, sensitivity 77.4% and specificity 66.7%. Physician based assessment revealed that subchondral sclerosis was present in 16% of K&L grade 1 patients, 52% of grade 2, 70% of grade 3 and 100% of grade 4 patients. No correlation could be found between physician based assessment and digital image analysis of subchondral sclerosis. Conclusions. Interobserver reliability in assessment of ankle OA using the K&L scale was similar to other previously described joints. OA progression correlated with functional diminution. Joint space narrowing assessed AIDA as well as the cut-off of 2mm correlated well with the K&L scale. Overall, we recommend the use of the K&L scale for the radiographic assessment of ankle OA

Power production in the terminal stance phase is essential for propelling the body forward during walking and is generated primarily by ankle plantarflexion. Osteoarthritis (OA) of the ankle restricts joint range of motion and is expected to reduce power production at that ankle. This loss of power may be compensated for by unaffected joints on both the ipsilateral and contralateral limbs resulting in overloading of the asymptomatic joints. Total ankle arthroplasty (TAA) has been shown to reduce pain and has the potential to restore range of motion and therefore increase ankle joint power, which could reduce overloading of the unaffected joints and increase walking speed. The purpose of this study was to test the hypothesis that ankle OA causes a loss of power in the affected ankle, compensatory power changes in unaffected lower limb joints, and that TAA will increase ankle power in the repaired ankle and reduce compensatory changes in other joints.

One hundred and eighty-three patients (86 men, 97 women with average ages 64.1 and 62.4 years respectively) requiring surgical intervention for ankle OA were prospectively enrolled. Implant selection of either a fixed (INBONE or Salto Talaris) or mobile (STAR) bearing implant was based on surgeon preference. Three-dimensional kinematics and kinetics were collected prior to surgery and one year post-operatively during self-selected speed level walking using an eight-camera motion capture system and a series of force platforms. Subject walking speed and lower extremity joint power during the last third of stance at the ankle, knee, and hip were calculated bilaterally and compared before and after surgical intervention across the entire group and by implant type (fixed vs. mobile), and gender using a series of ANOVAs (JMP SAS, Cary, NC), with statistical significance defined as p < 0 .05.

There were no gender differences in age, walking speed, or joint power. All patients increased walking as a result of surgery (0.87 m/s±0.26 prior to surgery and 1.13 m/s±0.24 after surgery, p < 0 .001) and increased total limb power. Normalized to total power (which accounts for changes in speed and distribution of power production across joints), prior to surgery the affected ankle contributed 19%±10% of total power while the unaffected ankle contributed 42%±12% (P < 0 .001). After surgery, the affected ankle increased to 25%±9% of total power and the unaffected ankle decreased to 38%±9% of total (P < 0.001). Other joints showed no significant power changes following surgery. Fixed bearing implants provide greater surgical ankle power improvement (61% versus 29% increase, p < 0 .002). Much of that change was due to the fact that those that received fixed-bearing implants had significantly lower walking speed and power before surgery.

Ankle OA reduced ankle power production, which was partially compensated for by the unaffected ankle. TAA increases walking speed and power at the affected ankle while lowering power production on the unaffected side. The modifications in power production could lead to increased physical activity and reduced overloading of asymptomatic joints.

Osteoarthritis (OA) is a disease of the joints stemming from a variety of factors, including joint injuries and abnormally high mechanical loading. Although the traditional treatment alternatives for end-stage OA are arthroplasty in the case of the hip and knee, and arthroplasty or arthrodesis in the case of the ankle, these options are not ideal for younger, more active patients. For these patients, joint prostheses would be expected to fail relatively quickly, and ankle fusion is not amenable to maintaining their active lifestyles. In these cases, joint distraction has attracted investigative attention as a conservative OA treatment for younger patients^9-14.

Based on the principle that decreasing the mechanical load on cartilage stimulates its regeneration¹⁵, distraction treatment calls for reduced loading of the joint during a period of typically 3 months, during which time the load customarily passing through the joint is taken up by an external fixator spanning the joint . By mounting the fixator components to the bone on each side of the joint, and then lengthening the rods connecting the proximal and distal portions of the fixator, the joint is distracted. Assuming the fixation is appropriately stiff, any load passes through the fixator instead of the joint, and the two articular surfaces will not be allowed to contact each other under physiologic loading. The exact mechanisms leading to cartilage regeneration during distraction are not yet understood.

A possible negative consequence of joint fixation is cartilage degeneration due to immobilization during the treatment. It has been shown by Haapala et al. and others that long-term immobilization can be detrimental to articular cartilage^16-18.

Conversely, joint motion during fixation (even passive motion) is thought to stimulate or encourage cartilage regeneration^19-22. Toward this end, considerable effort has been invested in the application of hinges to external fixation for joints Joint motion has also been suggested as a potentially beneficial factor in distraction treatment, as well¹⁰. This is borne out by data from an RCT comparing the use of a rigid vs motion external fixator. Change in joint biology due to resorption of cysts may be responsible for reversal of symptoms.

The relationship between hindfoot and forefoot kinematics is an important factor in the planning of ankle arthrodesis and ankle arthroplasty surgery. As more severe ankle deformities are corrected, improved techniques are required to assess and plan hindfoot to forefoot balancing.

Gait analysis has previously been reported in patients with ankle arthritis without deformity. This group of patients have reduced intersegment motion in all measured angles. We have looked at a small group of patients with hindfoot deformity and ankle arthritis awaiting fusion or replacement.

Using the Oxford Foot Model we have assessed lower limb kinematics with a focus on hindfoot to forefoot relationships. The results of our pilot study are in variance to previous studies in that we have shown that in the presence of hindfoot/ankle deformity, the forefoot range of motion increases. We feel that these data may impact on surgical planning.

Purpose: To evaluate the safety and efficacy of hylan G-F 20 viscosupplementation in patients with symptomatic osteoarthritis (OA) of the ankle.

Methods: Prospective, multi-center, open study in patients with primary or secondary grade II talocrural OA confirmed by X-ray. At baseline, patients had to score between 50–90 mm on the Patient-completed Ankle OA Pain VAS (0–100 mm). Patients received one intra-articular injection of 2 ml of hylan G-F 20 and were given an option of a second and final 2 ml injection if their pain remained between 50-90 mm on the VAS after 1, 2 or 3 months. Intraarticular injections were placed in the anteromedial portal of the ankle joint as described for ankle arthroscopy. Patients were followed for 6 months after the final injection. As rescue medication, patients could only take paracetamol up to 4 g per day, except on the day of or the day before a study visit.

All treatment emergent adverse events (AEs) were recorded. The primary efficacy endpoint was change from baseline (at final injection) in the Ankle OA Pain VAS at 3 months after the final injection. Secondary endpoints were Ankle OA Pain VAS scores at all other time-points, total Ankle OA Scale, Patient and Physician Global OA Assessment (VAS), and health-related quality of life (SF-36).

Results: Fifty-five patients (33 M; 22 F) were enrolled and received a first injection of hylan G-F 20. Twenty-four patients (44%) received a second injection. The mean age was 41 years (range 19–70). Overall, treatment with hylan G-F 20 was well tolerated. Seventeen patients (31%) had a treatment related AE of the target ankle. All were of mild or moderate intensity, the majority consisting of arthralgia and injection site pain. There was a statistically significant decrease in Ankle OA Pain VAS score from 68.0 mm at Baseline to 33.8 mm at Month 3 (p< 0.001, paired t-test), which was maintained at 6 months follow-up. The decrease was statistically significant at all time points. Patients who received only 1 injection demonstrated a greater decrease at 3 months (−42.5 mm) than patients with 2 injections (−23.5 mm). The secondary efficacy endpoints showed similar results. Of the total study population, 29 patients (53%) were responders (i.e. at least a 50% decrease in ankle OA pain) after 3 months. 64% of patients receiving 1 injection were responders after 3 months. The SF-36 questionnaire showed statistically significant improvements for both the physical and mental component scores at 3 and 6 months follow-up.

Conclusions: Treatment of OA of the ankle with intraarticular hylan G-F 20 injections is well tolerated. Treatment with hylan G-F 20 significantly decreases pain which is maintained for up to 6 months.

Syndesmotic ankle lesions involve disruption of the osseous tibiofibular mortise configuration as well as ligamentous structures stabilizing the ankle joint. Incomplete diagnosis and maltreatment of these injuries is frequent, resulting in chronic pain and progressive instability thus promoting development of ankle osteoarthritis in the long term. Although the pathogenesis is not fully understood, abnormal mechanics has been implicated as a principal determinant of ankle joint degeneration after syndesmotic ankle lesions. Therefore, the focus of this presentation will be on our recent development of a computationally efficient algorithm to calculate the contact pressure distribution in patients with a syndesmotic ankle lesion, enabling us to stratify the risk of OA development in the long term and thereby guiding patient treatment

One-fourth of all ankle trauma involve injury to the syndesmotic ankle complex, which may lead to syndesmotic instability and/or posttraumatic ankle osteoarthritis in the long term if left untreated. The diagnosis of these injuries still poses a deceitful challenge, as MRI scans lack physiologic weightbearing and plain weightbearing radiographs are subject to beam rotation and lack 3D information. Weightbearing cone-beam CT (WBCT) overcomes these challenges by imaging both ankles during bipedal stance, but ongoingdebate remains whether these should be taken under weightbearing conditions and/or during application of external rotation stress. The aim of this study is study therefore to compare both conditions in the assessment of syndesmotic ankle injuries using WBCT imaging combined with 3D measurement techniques. In this retrospective study, 21 patients with an acute ankle injury were analyzed using a WBCT. Patients with confirmed syndesmotic ligament injury on MRI were included, while fracture associated syndesmotic injuries were excluded. WBCT imaging was performed in weightbearing and combined weightbearing-external rotation. In the latter, the patient was asked to internally rotate the shin until pain (VAS>8/10) or a maximal range of motion was encountered. 3D models were developed from the CT slices, whereafter. The following 3D measurements were calculated using a custom-made Matlab® script; Anterior tibiofibular distance (AFTD), Alpha angle, posterior Tibiofibular distance (PFTD) and Talar rotation (TR) in comparison to the contralateral non-injured ankle. The difference in neutral-stressed Alpha angle and AFTD were significant between patients with a syndesmotic ankle lesion and contralateral control (P=0.046 and P=0.039, respectively). There was no significant difference in neutral-stressed PFTD and TR angle. Combined weightbearing-external rotation during CT scanning revealed an increased AFTD in patients with syndesmotic ligament injuries. Based on this study, application of external rotation during WBCT scans could enhance the diagnostic accuracy of subtle syndesmotic instability

An increasingly used treatment for end-stage ankle osteoarthritis is total ankle replacement (TAR). However, implant loosening and subsidence are commonly reported complications, leading to relatively high TAR failure rates. Malalignment of the TAR has often been postulated as the main reason for the high incidence of these complications. It remains unclear to what extent malalignment of the TAR affects the stresses at the bone-implant interface. Therefore, this study aims to elucidate the effect of TAR malalignment on the contact stresses on the bone-implant interface, thereby gaining more understanding of the potential role of malalignment in TAR failure. FE models of the neutrally aligned as well as malaligned CCI Evolution TAR implant (Van Straten Medical) were developed. Separate models were developed for the tibial and talar segment, with the TAR components in neutral alignment and 5° and 10° varus, valgus, anterior and posterior malalignment, resulting in a total of 9 differently aligned TAR models. Loading conditions of the terminal stance phase of the gait cycle, when the force on the ankle joint is highest (5.2x body weight), were applied. Peak and mean contact pressure and shear stress at the bone-implant interface were analyzed. Also, stress distributions on the bone-implant interface were visualized. In the neutrally aligned tibial and talar TAR models, peak contact pressures of respectively 98.4 MPa and 68.2 MPa, and shear stresses of respectively 49.3 MPa and 39.0 MPa were found. TAR malalignment increases peak contact pressure and shear stress on the bone-implant interface. A maximum peak contact pressure of 177 MPa was found for the 10° valgus malaligned tibial component and the highest shear stress found was 98.5 MPa for the 10° posterior malaligned talar model. Upon TAR malalignment contact stresses increase substantially, suggesting that proper orientation of the TAR is needed to minimize peak stresses on the bone-implant interface. This is in line with previous studies, which state that malalignment considerably increases bone strains, micromotion, and internal TAR contact pressures, which might increase the risk of TAR failure. Further research is needed to investigate the relationship between increased contact stresses at the bone-implant interface and TAR failure

Preoperative talar valgus deformity increases the technical difficulty of total ankle replacement (TAR) and is associated with an increased failure rate. Deformity of ≥15° has been reported to be a contraindication to arthroplasty. The goal of the present study was to determine whether the operative procedures and clinical outcomes of TAR for treatment of end-stage ankle arthritis were comparable for patients with preoperative talar valgus deformity of ≥15° as compared to those with <15°. We will describe the evolving surgical technique being utilized to tackle these challenging cases. Fifty ankles with preoperative coronal-plane tibiotalar valgus deformity of ≥15° “valgus” group) and 50 ankles with valgus deformity of <15° (“control” group) underwent TAR. The cohorts were similar with respect to demographics and components used. All TARs were performed by a single surgeon. The mean duration of clinical follow-up was 5.5 years (minimum two years). Preoperative and postoperative radiographic measurements of coronal-plane deformity, Ankle Osteoarthritis Scale (AOS) scores and Short Form (SF)-36 scores were prospectively recorded. All ancillary (intraoperative) and secondary procedures, complications and measurements were collected. The AOS pain and disability subscale scores decreased significantly in both groups. The improvement in AOS and SF-36 scores did not differ significantly between the groups at the time of the final follow-up. The valgus group underwent more ancillary procedures during the index surgery (80% vs 26%). Tibio-talar deformity improved significantly toward a normal weight-bearing axis in the valgus group. Secondary postoperative procedures were more common in the valgus group (36%) than the controls (20%). Overall, re-operation was not associated with poorer patient outcome scores. Metal component revision surgery occurred in seven patients (three valgus and four controls). These revisions included two deep infections (2%), one in each group, which were converted to hindfoot fusions. Therefore, 94% of the valgus group retained their original components at final follow-up. Thus far, this is the largest reported study that specifically evaluates TAR with significant preoperative valgus alignment, in addition to having the longest follow-up. Satisfactory midterm results were achieved in patients with valgus mal-alignment of ≥15°. The valgus cohort required more procedures during and after their TAR, as well as receiving more novel techniques to balance their TAR. Whilst longer term studies are needed, valgus coronal-plane alignment of ≥15° should not be considered an absolute contraindication to TAR if the associated deformities are addressed

Ankle arthrodesis and replacement are the widely accepted options in managing end-stage ankle arthritis. Ankle replacement as an alternate treatment option for ankle arthritis is relatively new and this is in large part to the successes observed with hip and knee arthroplasty for arthritis. Relative benefits of ankle replacement and arthrodesis remains a contentious topic. We conducted a multicenter pilot randomized controlled trial, first of its kind, comparing the clinical outcomes of ankle arthrodesis and ankle replacement in managing ankle arthritis. We hypothesized that clinical outcomes would be similar for both. Patients recruited for this study were part of Canadian Orthopaedic Foot and Ankle Society (COFAS) Database. Canadian orthopaedic surgeons with fellowship training in foot and ankle surgery or extensive experience in the surgical treatment of end stage ankle arthritis determined whether the patient met the criteria for randomization, skeletal maturity, symptomatic ankle arthritis no longer amenable to non-operative management, and ability to give informed consent. Data was collected on patient demographics, follow-up time period, complication rates, and Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) scores. Our analysis of clinical outcomes was divided into two parts: (1) comparison of pre and postoperative data for each cohort separately, and (2) comparison of outcome scores, and revision rates between both cohorts. We employed the Student's t-test and calculated effect sizes in assessing improvements in AOS and SF-36 scores from baseline to latest follow-up within and between the two groups. We also examined postoperative complication and reoperation rates in the study population using the standardized coding system for reoperations following ankle replacement and arthrodesis. Thirty-nine ankles were enrolled in the study with a mean follow-up of 5.1 ± 2.8 years. Ankle osteoarthritis scale scores improved significantly from baseline and last follow-up in both groups. The average baseline AOS total score for ankle replacement improved from 59.4 ±15.9 to 38 ±20 at last follow-up (p-value 19.7 to 31.8 ±16.5 at last follow-up (p-value 25.4 compared to ankle replacement's 20.3 ±23. Two major complications (10.5%) were observed in the ankle replacement cohort while the ankle arthrodesis cohort saw four major complications (20%). Clinical outcomes of ankle replacement and arthrodesis were comparable. The ankle arthrodesis cohort held a slight advantage over ankle replacement in improvement of AOS scores, though not statistically significant. Rates of major complications and reoperations were higher with ankle arthrodesis

Abstract. Objectives. Over 1% of the global population suffers with ankle osteoarthritis (OA), yet there is limited knowledge on the changes to subchondral bone with OA. In other joints, it has been shown that bone becomes osteosclerotic, with fewer, thicker trabeculae that become hypomineralised, causing an increased apparent bone volume fraction (BV/TV). Microstructural alterations reduce overall joint strength, which may impact the success of late-stage surgical interventions, such as total ankle arthroplasty (TAA). Previous ankle studies have evaluated changes to cartilage, bone plate and bone morphology with OA, hence this study aimed to characterise changes to trabecular architecture. Methods. Three ankle joints were isolated from non-diseased cadaveric feet (three males: 43, 50 and 57 years, MEEC 18-027). Cylindrical subchondral bone specimens (N=6, 6.5 mm Ø) were extracted from the tibial plafond. Osteoarthritic bone samples (N=6, distal tibia) were sourced from local patients (three males: 65, 58 and 68 years, NREC 07/Q1205/27) undergoing TAA surgery. Specimens were imaged using µCT at a 16 µm isotropic resolution (µCT-100 ScanCo Medical). Virtual cores of bone (6.5 mm Ø) were extracted from the image data of the osteoarthritic specimens and trimmed to a height of 4 mm. BoneJ was used to evaluate key morphological indices: BV/TV; anisotropy (DA); trabecular thickness (Tb.Th); trabecular density (Conn.D) and ellipsoid factor (EF) which characterises rod/plate geometry. Differences between the two groups of specimens were evaluated using a t-test with Bonferroni correction. Results. Significant increases in BV/TV and Tb.Th (p<0.01) were observed with OA compared to non-diseased. Differences in EF showed a shift to more rod-dominated structure with OA, but this was not significant. No significant differences to DA and Conn.D were observed. Conclusions. The results of this study agree with trends observed in other OA joints, but would benefit from a larger sample size. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project